Battle Not With Monsters
by DarknessIsTheUniverse
Summary: Charles and Raven are told not to look into the darkness, because one never knows what will stare back. Being children, they do worse. They try to open a window, and instead open a door. They are not for prepared what steps through from the other side. x Demon!AU. Erik as a demon and Charles' family as excorsists/supernatural watchers. Elements from Constantine/Insidious
1. Chapter 1

"Don't look into the darkness," their mother says, a steady mantra throughout their youths, a warning engrained into their heads long before they even _know_.

They are 12 years old when she tells them. It is their shared birthday, but instead of a party in the yard, Charles and Raven get the truth. It's not much of a gift.

Their father thinks it's too soon, but he will always think that and Sharon knows this. She tells them, not because she thinks that they are ready, but because they need to know. Because of the danger that not knowing holds. They are getting too old to be under the constant protection of their parents for much longer.

"Don't be afraid, darling," their mother tells Raven, who is clutching Charles' hand anxiously, "If you listen and learn, they will never touch you."

They learn much that night, about their ancestry, about life and death, about the here and the beyond, about the space in between, about mirrors, iron, salt, and age-old incantations. They'll never need them, their mother assures, because they will never follow the path of those that came before them.

It sounds like a fairy-tale to them, although a horrific one, unreal, intangible.

They have never met these ancestors, these generations before them that have given their lives, their blood, to fight an evil that most people don't even believe exists.

Charles and Raven possess what they did, what their mother possesses: the power to see, and the power to act. The power to find evil and banish it back into the abyss.

But history is not destiny.

"Never look," their mother tells them sternly, "If you don't see them, they won't see you."

It's the best choice she can make for them, all the warning she can give, but they are children and they don't understand the implication, the true horror that lies behind her weary eyes.

It's years before they truly catch a glimpse _beyond_ , and by then it is already much too late.


	2. Chapter 2

_'Don't look,'_ his mother's voice whispers in the darkness.

Charles is 27 but he might as well be ancient.

Restless and bone-tired, he twists and turns, cold sweat making his sheets stick to his back. He keeps his eyes tightly closed, even though he knows that there will be no sleep for him tonight.

He wants to listen, wants to not look.

It's pointless now of course, much too late for any kind of advice.

They're there, hovering, whispering, lurking in the darkness all around him, and closing his eyes won't make them go away. He does it anyway, too exhausted to fight the terror gripping hold of his cold limbs, the child inside him cowering, dying to curl up and press his hands to his ears. Dying to scream until his lungs bleed. Or until the whispering in his head stops.

Panting, he forces himself to lie still, to tell himself for the millionth time that the ghost touches freezing his skin are not real, that they can't be.

"My name is Charles Xavier. It is 03:47 AM. I am in my own apartment, in my own bed. I am here. I am here."

Not there.

Not with _them._

Not with _him._

He clutches the iron frame of his bed, solid proof that he is still in his world, that he is still alive.

Raven's face swims in the darkness above, laughing at him.

xxx

Charles is walking home from university when a silhouette separates itself from the shadows, crossing his path.

Charles grips the silver knife in his coat pocket tightly, instinctively, ready to defend himself against any form of danger.

It takes him a second to recognize Erik, piercing gray gaze finding his from out of a shadowed face.

For a second he freezes, filled with the urge to turn on his heel and run; then, he forces himself to straighten his shoulders and stand his ground. He doesn't pull out the knife, but his grip on it is tight as he stares at the figure in the shadows.

They stand immobile, eyes locked, for a long moment, until Erik breaks the silence.

"You really ought to not walk alone like this after dark," he says, his whiskey-smooth voice making Charles suppress a shiver, "There are all kinds of dangers lurking in the shadows."

Charles scowls, "I can take care of myself."

Erik eyes him darkly, with an imperceptible shake of his head. "I know you think that. But you're like a lighting bug in a night sky full of bats, Charles."

His eyes linger on the hand hidden in Charles' coat pocket, mouth twitching, before meeting his gaze again. Charles watches his pupils dilate, pin pricks in the light of the street lamp. For a second he looks less than human, like he himself might spread dark wings any second.

Charles feels his stomach turn at the expression, flight instinct jamming into him. He fights it down with an iron will. The mouse that bolts gets jumped.

"I recon they are all scared of you, so they'll keep away now," he bites out, meaning to sound contemptuous, but his voice is less steady than he'd hoped.

They _are_ all scared of him, aren't they?

The thought starts him walking again, fast. He can't do this. He makes a bee line around the other, avoiding contact at all cost. Distance. He needs to get away _now._

As always, he achieves the exact opposite of the effect that he was hoping for. Erik falls in step with him easily, gliding down the street in his impeccable winter coat like he belongs there.

"That they will," he says, now with a hint of satisfaction that is impossible to overhear.

"That was not an invitation," Charles scowls, walking faster.

Pointless. Forever pointless. Erik keeps up with no effort at all.

"Good thing I don't need one then," he says, matter-of-factly.

Charles suppresses a shudder, a scream possibly. He has barely enough sense to swallow down any response, any emotion until he is in front of his house, until he has unlocked his front door and stepped over the thick line of salt that protects his home. The one space that Erik cannot enter physically at least.

Only then does he dare turn around and speak his mind, glaring coldly.

"You think you have power here, but you don't. You never will."

He closes the door harshly, sick at the knowing smile dawning on the demon's face.


End file.
